JP3718002B2

JP3718002B2 - Threaded pile joint

Info

Publication number: JP3718002B2
Application number: JP16417096A
Authority: JP
Inventors: 田義明塚; 和真一大; 中昌穂田; 口武士井; 田剛池
Original assignee: Asahi Kasei Construction Materials Corp
Current assignee: Asahi Kasei Construction Materials Corp
Priority date: 1996-06-25
Filing date: 1996-06-25
Publication date: 2005-11-16
Anticipated expiration: 2016-06-25
Also published as: JPH108460A

Description

【０００１】
【発明の属する技術分野】
本発明はネジ接続される雄継手と雌継手との間に緩止め機構を介在させたネジ式杭継手に係り、特に接続が完了した後から逆転力が作用した場合にも継手部が緩むことのないように構成されたネジ式杭継手に関するものである。
【０００２】
【従来の技術】
従来も、例えば実開昭６０ー１９５３２８号公報、特公昭５０ー２５２５５号公報、実公昭４０ー６０４３号公報、実開昭６１ー８４７３４号公報、実開昭５６ー１３００３４号公報、特開平８ー６０６５２号公報、特公昭５６ー３６２４８号公報等に示す如く、雄継手と雌継手とをネジを用いて接続するネジ式継手が開発されている。
【０００３】
これ等の公知のネジ式継手は一般的に、予め杭を施工する場所の地盤に掘削された杭穴に設置される既製杭の接続に使用されるネジ式継手に関するものである。このように予め掘削された杭穴に杭を設置し、その周りにコンクリートミルクを注入して固定する方式に於いては、これに使用される杭継手の曲げに対しての耐力と垂直荷重に対しての圧縮耐力が機能的に要求されるのみで、杭自体及びこれ等の杭を接続している杭継手にも軸トルクが掛かることは無かった。
【０００４】
【発明が解決しようとする課題】
しかるに、前述の従来の公知技術に示すネジ式継手は、地中に掘削された杭穴に既製杭を設置する場合の接続には使用することが出来るが、地中に杭穴を設けずに、杭の外周に螺旋羽根を突設し、杭にねじりトルクを掛けながら螺旋羽根で地盤を切り進ませて杭の埋設を施工する無排土回転埋設工法に於いてこれ等を使用した場合には、次のような多くの問題があった。
【０００５】
即ち、無排土回転埋設工法に於いては、杭を埋設する場所の地盤の性状によっては、杭の施工時に杭を逆転させながら引き抜く作業を組み合わせながら施工する必要があるので、これ等の杭の継手部に対しても同様に正転及び逆転の力が作用し、該継手部に大きな軸トルクが掛かっていた。このような大きな軸トルクがネジ式の継手部に掛かった場合には、前述の従来の公知技術の杭継手では適切な逆転防止対策が充分に施されていないので、ネジ式接続部分では接続部が逆転して緩む問題があった。
【０００６】
前述の従来のネジ式杭継手には適切な逆転防止対策がないために、結局無排土回転埋設に使用される杭を接続する場合には、昔から実施された溶接接合に頼るしか手段がないのが実情であった。
【０００７】
しかし、既製杭を溶接によって接続する構造に於いては、全体の構造が簡単である反面で、杭の鉛直精度を守ることが困難である問題があった。更に杭の溶接作業を施工する場合には、熟練を要し、かつ感電事故が発生する心配のある雨天時には施工出来ない等の多くの問題もあった。
【０００８】
更に、仮にネジ式杭継手の中に緩止防止機構を組込んだ場合にも、回転角が問題であり、継手内に組込まれた逆転緩止機構が作用するまでに、接合面が開くほどに回転したのでは、仮に緩止めが出来たとしても、杭の正転時にその隙間に泥土が浸入して噛み込まれてしまい、これによって継手部にトラブルが発生し、また接合部の信頼を無くす問題もあった。
【０００９】
一般的に無排土回転埋設工法で杭を施工する時には、回転埋設装置で発生することのできる最大トルクの６０％程度で正転させて埋設しているが、杭を逆転させる必要があるという不測の事態が発生した場合には、１００％の逆トルクを掛けなければならなくなる。従って、逆転時の杭継手には、前記回転埋設装置が発生する最大トルクに充分耐えることが出来る緩止機構が必要である。
【００１０】
本発明に係るネジ式杭継手は、従来の前述の多くの問題点に鑑み開発された全く新しい技術であって、特に接合される杭の鉛直性を保つことが出来、かつ接合が極めて容易に施工出来、更に無排土回転埋設工法に於いて杭及びその継手部が逆転された際にも、継手部に緩みが生ずることがないようにしたネジ式杭継手の技術を提供するものである。
【００１１】
【課題を解決するための手段】
本発明に係るネジ式杭継手は、前述の従来の問題点を根本的に改善した技術であって、その第１発明の要旨は、相互にネジ接続される雄継手と雌継手との間にリング状逆転緩止部材が介在された杭継手に於いて、前記リング状逆転緩止部材の片表面には３°〜６°の下り勾配を有する複数個の突起部が設けられ、該複数個の突起部が設けられたリング状逆転緩止部材の片表面全体の面積は前記雄継手と雌継手とのネジ接触面の総面積の３分の１以上の面積で、かつ前記雄継手と雌継手とで相互に押圧し合って接触される面の面積の１３０〜１６０％の面積を有していることを特徴としたネジ式杭継手である。
【００１２】
また、本発明の第２発明の要旨は、雄継手と雌継手との間に介在されるリング状逆転緩止部材は単数或いは２個一対のものより構成されることを特徴とした第１発明のネジ式杭継手である。
【００１３】
本発明に係るネジ式杭継手は、ネジ締方向に下り勾配を有する複数個の突起部が片表面に設けられかつ片表面に滑り止めが設けられたリング状逆転緩止部材をネジ式の雄継手と雌継手との間に介在させて構成したものである。
【００１４】
また、リング状逆転緩止部材は２個を一対として使用する場合と、単独のものを使用する場合とがある。前者の場合は各リング状逆転緩止部材を夫々雄継手と雌継手とに取付け、これ等の一対のリング状逆転緩止部材を相互に噛合させるようにして構成した場合である。また、後者の場合は、１個のリング状逆転緩止部材を雄継手或いは雌継手に取付け、かつリング状逆転緩止部材が取付けられていない、他方の継手の所定部分に、リング状逆転緩止部材の片表面に設けられた凹凸面と噛合し得る凹凸面を設けて構成した場合とである。
【００１５】
更に、リング状逆転緩止部材を取付ける場所と、或いは該リング状逆転緩止部材の片表面の凹凸面と噛合し得る凹凸面を設ける場所とは、雄継手と雌継手との夫々の２個所が可能である。即ち、雄継手に於いてはその先端部と外径基部とが可能であり、雌継手に於いては、内底部と先端部とが可能である。
【００１６】
本発明に於ける杭継手に於いては、ネジ締方向に下り勾配を有し、ネジのリード角より大きいリード角度を持ったリング状逆転緩止部材が雄継手と雌継手との間に配置されているので、杭及びこの杭の継手部に逆転トルクが作用した時に、このリング状逆転緩止部材が反発力を発生し、ネジの摩擦力に対抗して、継手部に緩みが発生することを防止出来る。
【００１７】
この本発明に係る杭継手は、構造物を支える杭であることから前述のように接合面で同心度、鉛直性を保たねば杭に作用する荷重を全て保証することはできない。一般には、建設省の指導により溶接継手効率と称してその部分の保証強度を５％低減している。これは、現場での溶接作業であり接合条件が管理しにくいこと、接合面の広さに対して柱体である２本の杭の鉛直性を黙視でしか確認できないことなどがその根拠として上げられている。
【００１８】
この本発明に係る杭継手においては、工場生産で、接合性を管理保証しているため、低減を考慮しなくてもよい。接合する場合に規定のトルクで締め付けると接合面には、ごくわずかな弾性変形が発生し、接合をより確実なものにすることができる。
【００１９】
即ち、杭が正転方向に回転しかつ雄継手と雌継手とがネジ部で規定のトルクで接合されている時には、雄継手と雌継手との間に介在されたリング状逆転緩止部材の片表面の複数の突起部が相互に噛合しており、これによってねじりトルクによって発生する軸力をその片表面で全て支えることが出来る。
【００２０】
しかし、杭が前述のように逆転する時には、雄継手と雌継手とに設けた複数個の突起部は相対的に相異なる方向へズレる動きをするので、この突起部が設けられたリング状逆転緩止部材の片表面でねじりトルクによって発生する軸力を全て支えることが困難になる。従ってリング状逆転緩止部材の片表面の接触面積は大きな面積にする必要がある。
【００２１】
前述した様に、本発明のネジ式杭継手に於いては、下り勾配を持った複数の突起部よりなる凹凸状のカム面を片表面に設けたリング状逆転緩止部材を雄継手と雌継手との間に介在させて雄継手と雌継手とをネジ接合するので、両者のカム面は相対運動によって突出した突起部を登り始め、ネジ部の軸方向のクリアランスがなくなるので、リング状逆転緩止部材のカムの噛合作用によって軸方向に発生する力とバランスした状態で雄継手と雌継手とを相互に緊縛して安定して固定することが出来る。
【００２２】
【発明の実施の形態】
図により本発明に係るネジ式継手の一実施例を具体的に説明すると、図１（Ａ），（Ｂ）は本発明に係る第１実施例の杭継手の構造を示す縦断面説明図、図２はリング状逆転緩止部材の斜視説明図、図３（Ａ），（Ｂ）は、図２のリング状逆転緩止部材の側面及び正面図、図４は雄継手の押圧し合って接触される面とネジ部の接触面との関係を示す説明図、図５は雄雌継手の押圧し合って接触される２個所の関係を示す説明図である。
【００２３】
図６は雄雌継手の押圧し合って接触される個所が１個所である場合と２個所である場合の強度を比較する説明図、図７（Ａ），（Ｂ）は本発明の第２実施例の杭継手を示す縦断面説明図、図８（Ａ），（Ｂ）は夫々第３実施例及び第４実施例の杭継手を示す縦断面説明図、図９（Ａ），（Ｂ）は第５実施例の杭継手を示す縦断面説明図、図１０（Ａ），（Ｂ）は第６実施例の杭継手を示す縦断面説明図、図１１（Ａ）は逆転緩止機構の動作説明図、図１１（Ｂ）は逆転緩止機構の勾配面での力関係を表示する図式、図１２は本発明の逆転緩止機構を備えた杭継手の捻じり試験の結果を示すグラフ図である。
【００２４】
図１（Ａ），（Ｂ）に於いて、１，２は夫々鋼管製の杭本体であり、杭本体１の端部には円筒状の雄継手３が取付けられており、かつ杭本体２の端部には円筒状の雌継手４が取付けられている。前記雄継手３の外周壁には、杭本体１の端部を嵌着し得る段部５と雌継手４の先端部を当接し得る外径基部６とが設けられ、かつ雄継手３の先端小径部の外周面にはネジ部７が設けられている。
【００２５】
前記雌継手４の外周壁には杭本体２が嵌着し得る段部８が設けられている。また雌継手４の内周面には、前記雌継手３のネジ部７に螺合し得るネジ部９が設けられている。前述のような構造を有する雄継手３と雌継手４とを相互に接続した場合には、雌継手４の先端部が雄継手３の外径基部６に当接されると同時に、雄継手３の先端部が雌継手４の内底部１０に当接され、雄継手３と雌継手４とがこれ等の２個所に於いて、相互に押圧し合わされるように構成されている。
【００２６】
上記実施例に於いて、雄継手３の外径基部６は雄継手３の長手方向に対して直角な平面（起立平面）を持って形成されている。また、この外径基部６の起立平面は杭本体１，２の管断面の肉厚と等しいかそれ以上の肉厚を有している。また杭本体１，２と雄雌継手３，４との接続外周部には、溶接の際に使用されるＶ開先溝１１が設けられている。
【００２７】
次に図１乃至図３に於いて、１２はリング状逆転緩止部材であって、図に示すように雌継手４の内底部１０内に嵌入し得るリング体より形成され、かつその片表面１２ａにはネジの締め方向に下り勾配が放射状に円周状に複数個突出させた凹凸面が穿設されると共に、その片裏面１２ｂには滑り止め用の凸起が施されている。この滑り止めによって片裏面１２ｂの摩擦が片表面１２ａより大きくなるように配慮されている。この滑り止めには、強度の高い材質よりなる球状物体をリング状逆転緩止部材１２の裏表面に圧入したり、溶接によってビードを盛り上げたりして形成することが出来る。図１（Ｂ）に於いては、該片裏面１２ｂの凸部が嵌入し得る凹部を雄継手３の先端部と雌継手４の内底部１０に穿設したが、この凹部は該凸部の圧着によって形成されたものであり、予め設ける必要はない。
【００２８】
前記リング状逆転緩止部材１２は雄継手３の先端部に取付けられている。かつ雌継手４の内底部１０の表面には、リング状逆転緩止部材１２の片表面１２ａに設けた凹凸面と噛合し得る凹凸面１０ａが形成されており、雄継手３と雌継手４とを相互にネジ接合した際には、これ等のリング状逆転緩止部材１２の片表面１２ａと、内底部１０の凹凸面１０ａとが噛合されるように構成されている。これによって雄雌継手３，４に逆転の力が加わった場合にも、両者の逆転緩みを防止することが出来るように構成されている。
【００２９】
図３（Ａ）に於いて、前述のリング状逆転緩止部材１２の片表面１２ａと及び雌継手４の内底部１０とに夫々設けられた複数の突起部の下り勾配の角度１２αは、夫々３°〜６°に形成されている。これ等の突起部の下り勾配の角度１２αは前記雄雌継手３，４のネジ部７，９のリード角より大きくなるような角度で形成されている。
【００３０】
その理由は、杭本体１，２及びこれ等の杭本体１，２を接続する雄雌継手３，４に逆転の力が作用した場合には、前記ネジ部７，９のリードよりも、リング状逆転緩止部材１２の片表面１２ａと雌継手４の内底部１０との接触面のリード量を大きくし、逆転の際の力が大きくなった場合に雄雌継手３，４を軸方向に安定した状態で緊縛することが出来るようにするためである。
【００３１】
リング状逆転緩止部材１２と雌継手４の内底部１０とは前述のようにそれ等の凹凸面で噛合されているが、雄継手３の外径基部６と雌継手４の先端部とが相互に接触される雄雌継手３，４の外周部では、弾性変形を起こし、両者が相互に密着されて接合された状態になっている。この状態で杭本体１，２及び雄雌継手３，４を逆転させると、図３（Ａ）に示すような１２ｃの面は今迄の接触面が離別し、１２ｄの面が接する状態となる。
【００３２】
本発明に於いては、前述のようにリング状逆転緩止部材１２と雌継手４の内底部１０とに設けた突起部の下り勾配角度１２αを３°〜６°に設定したが、種々の実験を行った処、外径１００ｍｍ〜２７０ｍｍ、ネジ部７，９のネジピッチ（１条ネジのためにリードとピッチは同じ量）６ｍｍの杭本体１，２においては、３．５°〜４°付近のものが最も効果的であることが判明した。実験的には、５．７１°の角度のものも有効であり、凹凸カム面の摩擦力やリング状逆転緩止部材１２の設置される状況等によって、摩擦角度が大きく変化するので、これ等のことを考えると３°〜６°の範囲のものが好適である。
【００３３】
次にリング状逆転緩止部材１２の形状について、種々の観点から検討し、かつ実験すると、リング状逆転緩止部材１２の片表面１２ａの全体の面積を特定する必要があることが判明した。即ち、リング状逆転緩止部材１２と雌継手４の内底部１０とが接触する面積は、杭本体１，２自体の設計に大きく関係している。
【００３４】
例えば、締結トルクが３トン−ｍの鋼管杭１，２でネジ部７，８の有効径が２４３ｍｍ、ネジのリードが６ｍｍの場合に、軸方向に発生する力は約７２トンとなる。これによってネジ部７，９のネジ山数は杭１，２の所要耐力から実験的に決定される。
【００３５】
その結果、リング状逆転緩止部材１２の片表面１２ａの全体の面積は、雄継手３と雌継手４とのネジ部７，９の接触面の総面積３分の１以上が必要であり、更に雄継手３と雌継手４とが、外周部の雄継手３の外径基部６と雌継手４の先端部とで相互に押圧し合って接触される面の面積１３０〜１６０％の面積を有していることが必要であることが判明した。
【００３６】
リング状逆転緩止部材１２の片表面１２ａの面積がネジ部７，９の接触面積の３分の１以上が必要とされる根拠は、雄継手３と雌継手４との外周部の接触面積とリング状逆転緩止部材１２の片表面１２ａと雌継手４の内底部１０との接触面積との合計面積が、ネジ部７，９の接触面積より大きくなる場合には、ネジ部７，９のネジ面に発生する接触応力がリング状逆転緩止部材１２と雌継手４の内底部１０との接触面に発生する応力を越える場合に、ネジ部７，９で接合される雄雌継手３，４の本来の接合目的を逸して、ネジ部７，９の接合部に変形が生ずるからである。
【００３７】
また、前述のようにリング状逆転緩止部材１２の片表面１２ａの面積がネジ部７，９の接触面の３分の１以上必要であることを図示すると、図４に示す通りである。即ち図４に於いて、Ａ１は雄継手３の先端部と雌継手４の内底部１０との接合押圧部を示し、Ａ２は雄継手３の外径基部６と雌継手４の先端部との接合押圧部を示し、Ａ３は雄継手３，４のネジ部７，９の噛合部を示している。
【００３８】
また、リング状逆転緩止部材１２の片表面１２ａの面積、即ちリング状逆転緩止部材１２と雌継手４の内底部１０との接触面積が雄継手３の外径基部６と雌継手４の先端部との接触面積の１３０％〜１６０％の面積としなければならない理由は、雄雌継手３，４が少し逆転して相対的位置が変化した時、リング状逆転緩止部材１２の接触面では、雄継手３の外径基部６の接触面積と同一となり、この外径基部６の接触面で発生している応力と、リング状逆転緩止部材１２の接触面で発生している応力とほぼ平衡することになり、継手全体としてみる場合に、応力分布を均一に近くすることが出来るためである。
【００３９】
前述のようにリング状逆転緩止部材１２と雌継手４の内底部１０との接触面積（リング状逆転緩止部材１２の片表面１２ａの面積）が雄継手３の外径基部６と雌継手４の先端部との接触面積１３０〜１６０％の面積を必要とする理由を示すと図５に示す通りである。即ち、雄雌継手３，４に逆転力が生じることにより、リング状逆転緩止部材１２の接触面１２ａに於いて雄継手３の先端部とズレが生じることにより、接触面１２ａの面積が減少する。ここで本発明による面積比率でリング状逆転緩止部材１２を作製すれば、該リング状逆転緩止部材１２により緩み止め機構が最も効果的に作用するズレが生じた位置において、リング状逆転緩止部材１２と雌継手４の内底部１０との接触面積と、雄継手３の外径基部６と雌継手４の先端部との接触面積はほぼ等しくなることから、両者の接触面における応力状態は図５に示すように、リング状逆転緩止部材１２の接触面１２ａにおける応力Ｆ１に対し、雄継手３の先端部では接触面が相対的に大きいため、応力Ｆ１′はＦ１よりも小さく、雄継手３の外径基部６もしくは雌継手４の先端部における応力Ｆ２、Ｆ２′も同様にＦ１程度の応力状態となって、両接触面に極端な偏応力が生じないことから、部材の強度を十分に発現させることが可能となる。
【００４０】
図６のグラフに示すように、雄継手３と雌継手４とを夫々２個所で押圧し合わせることによって、杭継手の接続に大きな強度を持たせることが出来ることも明らかである。即ち、グラフ▲１▼は雄雌継手３，４を１個所で押圧し合わせる場合であり、グラフ▲２▼は雄雌継手３，４を２個所で押圧し合わせる場合であり、継手部の曲げ試験を行った処、後者の方が前者よりも継手部の曲げ強度が３０％程度高い値を示していることが明らかである。
【００４１】
上記第１実施例に於いては、リング状逆転緩止部材１２を雄継手３の先端部に取付け、雌継手４の内底部１０に凹凸面を設けて構成したが、図７（Ａ），（Ｂ）に示す第２実施例の如く、リング状逆転緩止部材１３を雌継手４の内底部１０に取付け、かつリング状逆転緩止部材１３の片表面１３ａに設けた凹凸面と噛合し得る凹凸面３ａを雄継手３の先端部に設け、これ等を組合せることによっても同様な作用効果を得ることが出来る。
【００４２】
図８（Ａ），（Ｂ）に示す第３実施例及び第４実施例は、夫々リング状逆転緩止部材１４，１５を雄継手３の外径基部６と雌継手４の先端部との間に介在させた場合の実施例である。同図（Ａ）に於いては、リング状逆転緩止部材１４を雌継手４の先端部に取付けると共に、このリング状逆転緩止部材１４の片表面１４ａに設けた凹凸面と噛合し得る凹凸面６ａを外径基部６に設けることによって構成している。同図（Ｂ）に於いては、リング状逆転緩止部材１５を雄継手３の外径基部６に取付け、雌継手４の先端部に凹凸面４ａを設けることによって構成している。これ等の図８（Ａ），（Ｂ）に示す第３及び第４実施例の場合には、リング状逆転緩止部材１４，１５の片表面１４ａ，１５ａの凹凸面の面積が、雄継手３の先端部と雌継手４の内底部１０との押圧接合面の１３０〜１６０％になるように構成されている。
【００４３】
上記実施例に於いては、１個のリング状逆転緩止部材１２，１３，１４，１５を夫々独立させて雄雌継手３，４との間に挿入して使用しているが、図９（Ａ），（Ｂ）及び図１０（Ａ），（Ｂ）の第５及び第６実施例に示す如く、一対のリング状逆転緩止部材１６，１７或いはリング状逆転緩止部材１８，１９を夫々使用し、これ等のリング状逆転緩止部材１６，１７，１８，１９を雄継手３或いは雌継手４の所定位置に対応させた状態で取付けることによって、組立構成することも可能である。
【００４４】
図１１（Ａ）に示す図は、逆転緩止機構の動作説明図であって、杭継手のネジのリードを６ｍｍ、リング状逆転緩止部材のリードを４８ｍｍとして設定した場合について数値で説明すると次の通りである。リードとはネジが３６０度回転したときに進む量である。例えば一対のリング状逆転緩止部材が相対的に１５度ずれたときに作用したとすると、ネジは０．２５ｍｍ緩むが、リング状逆転緩止部材は２ｍｍ緩むことになり、その差分１．７５ｍｍが緊縛力として雄雌継手のネジ部分に作用することが明らかである。
【００４５】
上述の関係を更に数式で詳述すると次の通りである。即ち、第１実施例に於けるリング状逆転緩止部材１２の片表面１２ａの突起部の数は、その片表面１２ａと雌継手４の内底部１０との接触面積と接触面圧力との関係によって、接触面を荒らさない程度の接触応力２０ｋｇ／ｍｍ²から決定される。この場合には１６山として構成した。
【００４６】
図１１（Ａ）に於けるＡ点で雄雌継手３，４を接触させた後、更に０．５ｍｍ締め込んで位置決めをする。Ｂ点は逆転を行い０．２５ｍｍ戻った位置とする。そして前述のようにネジのリードを６ｍｍ、リング状逆転緩止部材１２のリードを４８ｍｍとすると、６÷０．２５＝２４、３６０°÷２４＝１５°、４８×１５°÷３６０°＝２ｍｍ、即ち、ネジ面が０．５ｍｍ締め込まれた位置から０．２５ｍｍ逆転されると円周方向には、１５°戻ったことになり、リング状逆転緩止部材１２のリードから計算すると、図３（Ａ）に示すリング状逆転緩止部材１２の面１２ｄか２ｍｍずれたことになる。しかし、雄雌継手３，４のネジ部７，９のリードも同様の方向に移動しているので、実際には２ｍｍ−０．２５ｍｍ＝１．７ｍｍ分の緊縛力が内部に発生していることになる。
【００４７】
また、図１１（Ｂ）に示す図は、逆転緩止機構の勾配面での力関係を表示する図式であり、リング状逆転緩止部材の片裏面に要求される摩擦抵抗力の関係を示す図である。リング状逆転緩止部材の片表面の滑り止めは、図１１（Ｂ）で勾配面の力関係を現すことで明らかなように、ネジの締め付け力によって発生する軸方向の力Ｗと、勾配の角度α°と面の摩擦係数μとの関係として与えられる。すなわち上記の各記号間にはＦ＝Ｗ×ｔａｎαの関係がある。これより、片裏面の滑り止めに要求される摩擦抵抗力は、この値より大きい数値を与えるように設定する必要があり、実験の結果はＦ＝Ｃｎ＋ｔａｎ５．７１で表されることがわかった。ここにＣは滑り止め１個当たりの摩擦力であり、ｎは滑り止めを設置する個数である。
【００４８】
本発明に係る第１実例の杭継手についてねじり試験をした処、図１２のグラフに示すような結果が得られた。即ち、このグラフでは、約３トン−ｍのトルクを杭継手に作用させて締結を行った後、緩めるために逆転のトルクを作用させた経過を示したものである。このグラフで明らかなように、締め付けトルク約３トン−ｍで締められた継手は、約５トン−ｍの逆転トルクを受けても緩まないことが明らかとなった。
【００４９】
【発明の効果】
本発明に係るネジ式杭継手は、前述のような構造と作用とを有するので、本発明のネジ式杭継手を実施することによって、次のような多大な効果を有することが出来る。
【００５０】
（１）本発明に於いては、雄雌継手の相互間にリング状逆転緩止部材を介在させたので、このリング状逆転緩止部材の作用により雄雌継手の接続部に逆転による緩みが生ずることを防止出来る。（２）特に請求項１に記載された条件を満足させるように雄雌継手を接続することによって、両者を相互に完全に接合させることが出来、杭打ちの状況によって継手部に逆転力を必要とする場合にも、接続部に緩みが生ずることがない。（３）杭打ちの現場での天候や、施工技術者の勘や技量に左右されることなく、簡単かつ正確に杭を接合することが出来る。
【図面の簡単な説明】
【図１】図１（Ａ），（Ｂ）は本発明に係る第１実施例の杭継手の構造を示す縦断面説明図である。
【図２】リング状逆転緩止部材の斜視説明図である。
【図３】図３（Ａ），（Ｂ）は図２のリング状逆転緩止部材の側面図及び正面図である。
【図４】雄雌継手の押圧し合って接触される面とネジ部の接触面との関係を示す説明図である。
【図５】雄雌継手の押圧し合って接触される２個所の関係を示す説明図である。
【図６】雄雌継手の押圧し合って接触される個所が１個所である場合と２個所である場合の強度を比較する説明図である。
【図７】図７（Ａ），（Ｂ）は本発明の第２実施例の杭継手を示す縦断面説明図である。
【図８】図８（Ａ），（Ｂ）は夫々第３実施例及び第４実施例の杭継手を示す縦断面説明図である。
【図９】図９（Ａ），（Ｂ）は第５実施例の杭継手を示す縦断面説明図である。
【図１０】図１０（Ａ），（Ｂ）は第６実施例の杭継手を示す縦断面説明図である。
【図１１】図１１（Ａ）は逆転緩止機構の動作説明図、図１１（Ｂ）は逆転緩止機構の勾配面での力関係を表示する図式である。
【図１２】本発明の逆転緩止機構を備えた杭継手の捻じり試験の結果を示すグラフ図である。
【符号の説明】
1,2 杭本体
３雄継手
４雌継手
５段部
６外径基部
７ネジ部
８段部
９ネジ部
10 内底部
11 Ｖ開先溝
12,13,14,15,15 リング状逆転緩止部材
12a,13a,14a,15ａ片表面
12b,13b,14b,15b 片裏面
16,17,18,19 リング状逆転緩止部材
16a,17a,18a,19a 片表面
16b,17b,18b,19b 片裏面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a threaded pile joint in which a loosening prevention mechanism is interposed between a male joint and a female joint to be screwed, and in particular, the joint is loosened even when a reverse force is applied after the connection is completed. The present invention relates to a threaded pile joint that is configured so as not to have any.
[0002]
[Prior art]
Conventionally, for example, Japanese Utility Model Publication No. 60-195328, Japanese Patent Publication No. 50-25255, Japanese Utility Model Publication No. 40-6043, Japanese Utility Model Application Publication No. 61-84734, Japanese Utility Model Application Publication No. 56-130034, Japanese Patent Application Laid-Open No. Hei 8 As shown in Japanese Patent Publication No. 60652, Japanese Patent Publication No. 56-36248, etc., a threaded joint for connecting a male joint and a female joint using screws has been developed.
[0003]
These known threaded joints generally relate to threaded joints that are used to connect pre-made piles that are installed in pile holes that have been excavated in the ground where the piles are pre-constructed. In this way, piles are installed in pre-excavated pile holes, and concrete milk is poured around them to fix them. The compressive yield strength was only required functionally, and no axial torque was applied to the piles themselves and the pile joints connecting these piles.
[0004]
[Problems to be solved by the invention]
However, the threaded joint shown in the above-mentioned conventional publicly known technology can be used for connection when installing a pre-made pile in a pile hole excavated in the ground, but without providing a pile hole in the ground. When a spiral blade is installed on the outer periphery of the pile, and the ground is cut with the spiral blade while twisting torque is applied to the pile, and the pile is buried in the soil-free rotary burial method. There were many problems as follows.
[0005]
In other words, in the non-exhaust soil rotary burying method, depending on the properties of the ground where the piles are buried, it is necessary to construct the piles by combining the work of pulling them out while reversing the piles. Similarly, the forward and reverse forces acted on the joint part, and a large shaft torque was applied to the joint part. When such a large shaft torque is applied to the threaded joint, the above-mentioned conventional well-known pile joint does not have adequate anti-reverse measures, so the threaded joint has no connection. There was a problem of loosening by reversing.
[0006]
Since the conventional threaded pile joints mentioned above do not have appropriate anti-reverse measures, the only way to connect piles that will eventually be used for non-exhaust soil rotary burial is to rely on welded joints that have been used for a long time. There was no actual situation.
[0007]
However, in the structure in which ready-made piles are connected by welding, the overall structure is simple, but there is a problem that it is difficult to maintain the vertical accuracy of the piles. Furthermore, when performing the welding work of piles, there were many problems such as inability to perform construction in rainy weather that required skill and would cause an electric shock accident.
[0008]
Furthermore, even if a locking prevention mechanism is incorporated in a threaded pile joint, the rotation angle is a problem, and the joint surface opens until the reverse rotation locking mechanism incorporated in the joint acts. However, even if it was possible to prevent loosening, mud soil entered the gap during the forward rotation of the pile and this caused trouble in the joint, and the reliability of the joint became reliable. There was also a problem to lose.
[0009]
In general, when piles are constructed using the earthless rotary burying method, the piles are rotated forward at about 60% of the maximum torque that can be generated by the rotary burying equipment, but it is necessary to reverse the piles. If an unexpected situation occurs, 100% reverse torque must be applied. Accordingly, the pile joint at the time of reverse rotation needs a loosening mechanism that can sufficiently withstand the maximum torque generated by the rotary embedding device.
[0010]
The threaded pile joint according to the present invention is a completely new technology developed in view of the above-mentioned many problems of the prior art, and can maintain the verticality of piles to be joined, and can be joined very easily. Provided is a threaded pile joint technology that can be constructed, and further prevents loosening of the joint even when the pile and its joint are reversed in the earthless rotary burying method. .
[0011]
[Means for Solving the Problems]
The threaded pile joint according to the present invention is a technique that fundamentally improves the above-mentioned conventional problems, and the gist of the first invention is between a male joint and a female joint that are screw-connected to each other. In a pile joint in which a ring-shaped reverse rotation locking member is interposed, a plurality of protrusions having a downward gradient of 3 ° to 6 ° are provided on one surface of the ring-shaped reverse rotation locking member. The entire area of one surface of the ring-shaped reverse rotation locking member provided with the protrusions is one-third or more of the total area of the screw contact surfaces of the male joint and female joint, and the male joint and female It is a threaded pile joint characterized by having an area of 130 to 160% of the area of the surface that is pressed against and brought into contact with the joint.
[0012]
Further, the gist of the second invention of the present invention is that the ring-shaped reverse locking member interposed between the male joint and the female joint is composed of a single member or a pair of two members. This is a threaded pile joint.
[0013]
The threaded pile joint according to the present invention includes a ring-shaped reverse locking member having a plurality of protrusions having a downward slope in the screw tightening direction on one surface and a slip stopper on one surface. It is configured to be interposed between a joint and a female joint.
[0014]
Moreover, there are a case where two ring-shaped reverse rotation locking members are used as a pair and a case where a single one is used. In the former case, each ring-shaped reverse rotation locking member is attached to a male joint and a female joint, respectively, and the pair of ring-shaped reverse rotation locking members are engaged with each other. In the latter case, one ring-shaped reverse rotation-retaining member is attached to the male joint or female joint, and the ring-shaped reverse rotation-relaxation member is not attached to a predetermined portion of the other joint where the ring-shaped reverse rotation prevention member is not attached. This is a case where an uneven surface that can mesh with an uneven surface provided on one surface of the stop member is provided.
[0015]
Furthermore, the place where the ring-shaped reverse rotation / loosening member is attached or the place where the concave / convex surface capable of meshing with the uneven surface on one surface of the ring-shaped reverse rotation / loosening member is provided in two locations, a male joint and a female joint. Is possible. In other words, the male joint can have a tip portion and an outer diameter base portion, and the female joint can have an inner bottom portion and a tip portion.
[0016]
In the pile joint of the present invention, a ring-shaped reverse rotation locking member having a downward slope in the screw tightening direction and having a lead angle larger than the lead angle of the screw is disposed between the male joint and the female joint. Therefore, when reverse torque acts on the pile and the joint of this pile, this ring-shaped reverse rotation locking member generates a repulsive force, and the joint is loosened against the frictional force of the screw. Can be prevented.
[0017]
Since the pile joint according to the present invention is a pile that supports a structure, it is impossible to guarantee all loads acting on the pile unless the concentricity and the verticality are maintained at the joint surface as described above. Generally, under the guidance of the Ministry of Construction, the guaranteed strength of this part is reduced by 5%, referred to as welded joint efficiency. This is based on the fact that it is difficult to manage the joining conditions because it is an on-site welding operation, and that the verticality of the two piles, which are the pillars, can only be confirmed with respect to the width of the joining surface. It has been.
[0018]
In the pile joint according to the present invention, since the bondability is managed and guaranteed in factory production, reduction need not be considered. In the case of joining, if it is tightened with a prescribed torque, a very slight elastic deformation occurs on the joining surface, and the joining can be made more reliable.
[0019]
That is, when the pile rotates in the forward rotation direction and the male joint and the female joint are joined to each other with the prescribed torque at the threaded portion, the ring-shaped reverse locking member interposed between the male joint and the female joint A plurality of protrusions on one surface are meshed with each other, whereby all axial forces generated by torsional torque can be supported on the one surface.
[0020]
However, when the pile reverses as described above, the plurality of protrusions provided on the male joint and the female joint move in different directions, so that the ring-shaped reverse rotation provided with this protrusion is provided. It becomes difficult to support all axial forces generated by torsional torque on one surface of the locking member. Therefore, it is necessary to make the contact area of one surface of the ring-shaped reverse locking member large.
[0021]
As described above, in the threaded pile joint of the present invention, the ring-shaped reverse rotation locking member having a concave and convex cam surface made up of a plurality of downwardly projecting protrusions on one surface is connected to a male joint and a female joint. Since the male and female joints are screw-joined between the joints, the cam surfaces of both sides begin to climb up the protruding part due to relative motion, and the axial clearance of the thread part disappears, so the ring-shaped reverse rotation The male joint and the female joint can be tied together and stably fixed in a state balanced with the force generated in the axial direction by the engagement action of the cam of the locking member.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the threaded joint according to the present invention will be specifically described with reference to the drawings. FIGS. 1A and 1B are longitudinal sectional explanatory views showing the structure of the pile joint of the first embodiment according to the present invention. 2 is a perspective explanatory view of the ring-shaped reverse rotation locking member, FIGS. 3A and 3B are side and front views of the ring-shaped reverse rotation locking member of FIG. 2, and FIG. FIG. 5 is an explanatory view showing the relationship between the contact surface and the contact surface of the screw portion, and FIG.
[0023]
FIG. 6 is an explanatory view for comparing the strength when the male and female joints are in contact with each other by one place, and FIGS. 7A and 7B show the second embodiment of the present invention. FIG. 8A and FIG. 8B are longitudinal sectional explanatory views showing the pile joints of the third embodiment and the fourth embodiment, and FIG. 9A and FIG. ) Is a longitudinal sectional explanatory view showing a pile joint of the fifth embodiment, FIGS. 10A and 10B are longitudinal sectional explanatory views showing a pile joint of the sixth embodiment, and FIG. 11A is a reverse locking mechanism. FIG. 11B is a diagram showing the force relationship on the slope surface of the reverse rotation prevention mechanism, and FIG. 12 shows the result of a torsion test of the pile joint having the reverse rotation prevention mechanism of the present invention. FIG.
[0024]
In FIGS. 1 (A) and 1 (B), 1 and 2 are steel pipe pile bodies, a cylindrical male joint 3 is attached to the end of the pile body 1, and the pile body 2. A cylindrical female joint 4 is attached to the end of the. An outer peripheral wall of the male joint 3 is provided with a step portion 5 on which an end portion of the pile body 1 can be fitted and an outer diameter base portion 6 on which the distal end portion of the female joint 4 can be brought into contact. A screw portion 7 is provided on the outer peripheral surface of the small diameter portion.
[0025]
On the outer peripheral wall of the female joint 4, a step portion 8 to which the pile main body 2 can be fitted is provided. Further, on the inner peripheral surface of the female joint 4, a screw portion 9 that can be screwed into the screw portion 7 of the female joint 3 is provided. When the male joint 3 and the female joint 4 having the above-described structure are connected to each other, the distal end portion of the female joint 4 is brought into contact with the outer diameter base portion 6 of the male joint 3, and at the same time, the male joint 3 The front end of the female joint 4 is brought into contact with the inner bottom 10 of the female joint 4, and the male joint 3 and the female joint 4 are configured to be pressed against each other at these two locations.
[0026]
In the above embodiment, the outer diameter base portion 6 of the male joint 3 is formed with a plane (standing plane) perpendicular to the longitudinal direction of the male joint 3. The standing plane of the outer diameter base 6 has a thickness equal to or greater than the thickness of the pipe cross section of the pile bodies 1 and 2. Further, a V groove 11 used for welding is provided on the outer periphery of the connection between the pile bodies 1 and 2 and the male and female joints 3 and 4.
[0027]
Next, in FIGS. 1 to 3, reference numeral 12 denotes a ring-shaped reverse rotation-retaining member, which is formed of a ring body that can be fitted into the inner bottom 10 of the female joint 4 as shown in the figure, and one surface thereof. 12a is provided with a concavo-convex surface in which a plurality of descending gradients are projected radially in the screw tightening direction, and a non-slip protrusion is provided on one back surface 12b. By this anti-slip, it is considered that the friction of the back surface 12b is larger than that of the front surface 12a. This anti-slip can be formed by press-fitting a spherical object made of a high-strength material into the back surface of the ring-shaped reverse rotation-loosening member 12 or by raising the bead by welding. In FIG. 1 (B), a concave portion into which the convex portion of the one back surface 12b can be fitted is formed in the distal end portion of the male joint 3 and the inner bottom portion 10 of the female joint 4. It is formed by pressure bonding and need not be provided in advance.
[0028]
The ring-shaped reverse locking member 12 is attached to the tip of the male joint 3. The surface of the inner bottom portion 10 of the female joint 4 is formed with an uneven surface 10a that can mesh with the uneven surface provided on the one surface 12a of the ring-shaped reverse rotation locking member 12, and the male joint 3 and the female joint 4 When the two are screwed together, the one surface 12a of the ring-shaped reverse rotation locking member 12 and the concavo-convex surface 10a of the inner bottom portion 10 are engaged with each other. Thus, even when a reverse force is applied to the male and female joints 3 and 4, the reverse rotation and looseness of both can be prevented.
[0029]
In FIG. 3A, the downward gradient angles 12α of the plurality of protrusions respectively provided on the one surface 12a of the ring-shaped reverse rotation locking member 12 and the inner bottom portion 10 of the female joint 4 are respectively shown in FIG. It is formed at 3 ° to 6 °. The downward slope angle 12α of these protrusions is formed to be larger than the lead angle of the threaded portions 7 and 9 of the male and female joints 3 and 4.
[0030]
The reason for this is that when a reverse force is applied to the pile bodies 1 and 2 and the male and female joints 3 and 4 that connect these pile bodies 1 and 2, rather than the leads of the screw portions 7 and 9, the ring When the amount of lead on the contact surface between the one surface 12a of the reverse reversal locking member 12 and the inner bottom 10 of the female joint 4 is increased and the force during reverse rotation is increased, the male and female joints 3 and 4 are moved in the axial direction. This is so that it can be bound in a stable state.
[0031]
As described above, the ring-shaped reverse rotation locking member 12 and the inner bottom portion 10 of the female joint 4 are meshed with each other on their concave and convex surfaces, but the outer diameter base portion 6 of the male joint 3 and the distal end portion of the female joint 4 are connected. The outer peripheral portions of the male and female joints 3 and 4 that are in contact with each other are elastically deformed and are in close contact with each other and joined together. When the pile main bodies 1 and 2 and the male and female joints 3 and 4 are reversed in this state, the surface of 12c as shown in FIG. 3A is separated from the contact surface so far and the surface of 12d is in contact. .
[0032]
In the present invention, as described above, the downward slope angle 12α of the protrusion provided on the ring-shaped reverse rotation-retaining member 12 and the inner bottom portion 10 of the female joint 4 is set to 3 ° to 6 °. In the place where the experiment was conducted, in the pile main bodies 1 and 2 having an outer diameter of 100 mm to 270 mm and a screw pitch of the screw portions 7 and 9 (the lead and the pitch are the same amount because of a single thread), the angle is 3.5 ° to 4 °. Nearby ones proved to be most effective. Experimentally, an angle of 5.71 ° is also effective, and the friction angle changes greatly depending on the frictional force of the concave and convex cam surface and the situation where the ring-shaped reverse rotation locking member 12 is installed. In view of the above, a range of 3 ° to 6 ° is preferable.
[0033]
Next, the shape of the ring-shaped reverse rotation / loosening member 12 was examined and tested from various viewpoints, and it was found that the entire area of the one surface 12a of the ring-shaped reverse rotation / loosening member 12 needs to be specified. That is, the area where the ring-shaped reverse rotation locking member 12 and the inner bottom portion 10 of the female joint 4 are in contact with each other is greatly related to the design of the pile bodies 1 and 2 themselves.
[0034]
For example, when the steel pipe piles 1 and 2 having a fastening torque of 3 tons-m, the effective diameter of the screw portions 7 and 8 is 243 mm, and the lead of the screw is 6 mm, the force generated in the axial direction is about 72 tons. As a result, the number of threads of the threaded portions 7 and 9 is experimentally determined from the required yield strength of the piles 1 and 2.
[0035]
As a result, the total area of the one surface 12a of the ring-shaped reverse rotation locking member 12 needs to be at least one third of the total area of the contact surfaces of the threaded portions 7, 9 of the male joint 3 and the female joint 4, Furthermore, the area of 130 to 160% of the area where the male joint 3 and the female joint 4 are brought into contact with each other by pressing the outer diameter base 6 of the male joint 3 and the tip of the female joint 4 on the outer periphery. It turned out to be necessary.
[0036]
The reason why the area of the one surface 12a of the ring-shaped reverse rotation locking member 12 needs to be one third or more of the contact area of the screw portions 7 and 9 is that the contact area of the outer periphery of the male joint 3 and the female joint 4 When the total area of the contact area between the one surface 12a of the ring-shaped reverse rotation locking member 12 and the inner bottom part 10 of the female joint 4 is larger than the contact area of the screw parts 7, 9, the screw parts 7, 9 When the contact stress generated on the screw surface exceeds the stress generated on the contact surface between the ring-shaped reverse rotation locking member 12 and the inner bottom portion 10 of the female joint 4, the male / female joint 3 joined by the screw portions 7 and 9 is used. This is because the original purpose of joining of 4 and 4 is lost and deformation occurs at the joints of the screw portions 7 and 9.
[0037]
Further, as described above, it is as shown in FIG. 4 that the area of the one surface 12a of the ring-shaped reverse rotation locking member 12 is required to be one third or more of the contact surface of the screw portions 7 and 9. That is, in FIG. 4, A <b> 1 indicates a joint pressing portion between the distal end portion of the male joint 3 and the inner bottom portion 10 of the female joint 4, and A <b> 2 indicates between the outer diameter base portion 6 of the male joint 3 and the distal end portion of the female joint 4. A joining press part is shown, A3 has shown the meshing part of the thread parts 7 and 9 of the male joints 3 and 4. FIG.
[0038]
Further, the area of the one surface 12 a of the ring-shaped reverse rotation locking member 12, that is, the contact area between the ring-shaped reverse rotation locking member 12 and the inner bottom portion 10 of the female joint 4 is the same as that of the outer diameter base 6 of the male joint 3 and the female joint 4. The reason why the contact area with the tip portion should be 130% to 160% is that when the male and female joints 3 and 4 are slightly reversed and their relative positions are changed, the contact surface of the ring-shaped reverse rotation locking member 12 Then, it becomes the same as the contact area of the outer diameter base portion 6 of the male joint 3, and the stress generated on the contact surface of the outer diameter base portion 6 and the stress generated on the contact surface of the ring-shaped reverse rotation locking member 12 This is because the stress distribution can be made nearly uniform when viewed as the whole joint.
[0039]
As described above, the contact area between the ring-shaped reverse rotation locking member 12 and the inner bottom 10 of the female joint 4 (the area of the one surface 12a of the ring-shaped reverse rotation locking member 12) is the outer diameter base 6 of the male joint 3 and the female joint. FIG. 5 shows the reason why an area of 130 to 160% of contact area with the tip end of 4 is required. That is, when the reverse force is generated in the male and female joints 3 and 4, the contact surface 12a of the ring-shaped reverse rotation locking member 12 is displaced from the tip of the male joint 3, thereby reducing the area of the contact surface 12a. To do. Here, if the ring-shaped reverse rotation-retaining member 12 is produced with the area ratio according to the present invention, the ring-shaped reverse rotation-relaxation member 12 is located at the position where the ring-shaped reverse rotation-relaxation member 12 has the most effective displacement. Since the contact area between the stop member 12 and the inner bottom portion 10 of the female joint 4 and the contact area between the outer diameter base portion 6 of the male joint 3 and the distal end portion of the female joint 4 are substantially equal, the stress state at the contact surfaces of both As shown in FIG. 5, the stress F1 ′ is smaller than F1 because the contact surface is relatively large at the distal end portion of the male joint 3 with respect to the stress F1 on the contact surface 12a of the ring-shaped reverse rotation locking member 12. Similarly, the stresses F2 and F2 'at the outer diameter base 6 of the male joint 3 or the tip of the female joint 4 are in the same stress state as F1, and no extreme bias stress is generated on both contact surfaces. Can be fully expressed To become.
[0040]
As shown in the graph of FIG. 6, it is also clear that the strength of the connection of the pile joint can be increased by pressing the male joint 3 and the female joint 4 together at two locations. That is, the graph (1) is when the male and female joints 3 and 4 are pressed together at one place, and the graph (2) is the case when the male and female joints 3 and 4 are pressed together at two places. As a result of the test, it is clear that the latter shows a value about 30% higher in bending strength of the joint than the former.
[0041]
In the first embodiment, the ring-shaped reverse rotation locking member 12 is attached to the tip of the male joint 3 and the inner bottom 10 of the female joint 4 is provided with an uneven surface. As in the second embodiment shown in FIG. 5B, the ring-shaped reverse rotation locking member 13 is attached to the inner bottom 10 of the female joint 4 and meshed with the uneven surface provided on the one surface 13a of the ring-shaped reverse rotation locking member 13. A similar effect can be obtained by providing the uneven surface 3a to be obtained at the tip of the male joint 3 and combining them.
[0042]
In the third and fourth embodiments shown in FIGS. 8A and 8B, the ring-shaped reverse rotation locking members 14 and 15 are respectively connected to the outer diameter base portion 6 of the male joint 3 and the distal end portion of the female joint 4. This is an embodiment in the case of being interposed. In FIG. 2A, the ring-shaped reverse rotation locking member 14 is attached to the tip of the female joint 4, and the unevenness that can mesh with the uneven surface provided on one surface 14a of the ring-shaped reverse rotation locking member 14 is shown. The surface 6 a is formed on the outer diameter base 6. In FIG. 5B, a ring-shaped reverse rotation locking member 15 is attached to the outer diameter base portion 6 of the male joint 3, and the concave and convex surface 4 a is provided at the tip of the female joint 4. In the case of the third and fourth embodiments shown in FIGS. 8 (A) and 8 (B), the area of the concavo-convex surface of the one surface 14a, 15a of the ring-shaped reverse rotation locking member 14, 15 is the male joint. 3 and 130 to 160% of the press-bonding surface between the front end portion 3 and the inner bottom portion 10 of the female joint 4.
[0043]
In the above embodiment, one ring-shaped reverse rotation-retaining member 12, 13, 14, 15 is inserted and used between the male and female joints 3 and 4 independently. As shown in the fifth and sixth embodiments of FIGS. 10A and 10B, a pair of ring-shaped reverse rotation locking members 16, 17 or ring-shaped reverse rotation locking members 18, 19 The ring-shaped reverse rotation locking members 16, 17, 18, and 19 are attached in a state corresponding to the predetermined positions of the male joint 3 or the female joint 4. .
[0044]
FIG. 11 (A) is an explanatory view of the operation of the reverse rotation locking mechanism, and numerically describes the case where the lead of the pile joint screw is set to 6 mm and the lead of the ring-shaped reverse rotation locking member is set to 48 mm. It is as follows. The lead is an amount that advances when the screw rotates 360 degrees. For example, if the pair of ring-shaped reverse rotation locking members act when they are relatively displaced by 15 degrees, the screw is loosened by 0.25 mm, but the ring-shaped reverse rotation locking members are loosened by 2 mm, and the difference is 1.75 mm. It is clear that acts on the thread portion of the male-female joint as a binding force.
[0045]
The above relationship will be described in further detail with mathematical formulas as follows. That is, the number of protrusions on one surface 12a of the ring-shaped reverse rotation locking member 12 in the first embodiment is the relationship between the contact area between the one surface 12a and the inner bottom 10 of the female joint 4 and the contact surface pressure. 20kg / mm of contact stress that does not roughen the contact surface ² Determined from. In this case, it was configured as 16 mountains.
[0046]
After the male and female joints 3 and 4 are brought into contact at the point A in FIG. 11A, the positioning is further performed by tightening 0.5 mm. Point B is set to a position that is reversed and returned 0.25 mm. As described above, assuming that the lead of the screw is 6 mm and the lead of the ring-shaped reverse rotation locking member 12 is 48 mm, 6 ÷ 0.25 = 24, 360 ° ÷ 24 = 15 °, 48 × 15 ° ÷ 360 ° = 2 mm That is, when the screw surface is reversed 0.25 mm from the position where the screw surface is tightened 0.5 mm, the circumferential direction is returned by 15 °. This means that the surface 12d of the ring-shaped reverse rotation-retaining member 12 shown in FIG. However, since the leads of the threaded portions 7 and 9 of the male and female joints 3 and 4 are also moving in the same direction, a binding force of 2 mm−0.25 mm = 1.7 mm is actually generated inside. It will be.
[0047]
Moreover, the figure shown to FIG. 11 (B) is a figure which displays the force relationship in the gradient surface of a reverse rotation rotation prevention mechanism, and shows the relationship of the frictional resistance force requested | required by the one back surface of a ring-shaped reverse rotation rotation prevention member. FIG. The slip prevention of one surface of the ring-shaped reverse rotation-retaining member, as is apparent by expressing the force relationship of the sloped surface in FIG. 11B, the axial force W generated by the screw tightening force, It is given as a relation between the angle α ° and the friction coefficient μ of the surface. That is, there is a relationship of F = W × tan α between the above symbols. From this, it was found that the frictional resistance required for anti-slip on one back surface needs to be set so as to give a value larger than this value, and the experimental result is expressed as F = Cn + tan 5.71. Here, C is the frictional force per slipper, and n is the number of slippers to be installed.
[0048]
When the torsion test was performed on the pile joint of the first example according to the present invention, the result as shown in the graph of FIG. 12 was obtained. That is, this graph shows a process in which a reverse torque is applied to loosen after tightening by applying a torque of about 3 ton-m to the pile joint. As is apparent from this graph, it was revealed that the joint tightened with a tightening torque of about 3 tons-m does not loosen even when subjected to a reverse torque of about 5 tons-m.
[0049]
【The invention's effect】
Since the threaded pile joint according to the present invention has the above-described structure and action, the following great effects can be obtained by implementing the threaded pile joint of the present invention.
[0050]
(1) In the present invention, since a ring-shaped reverse rotation locking member is interposed between the male and female joints, the ring-shaped reverse rotation locking member causes loosening due to reverse rotation at the connecting portion of the male and female joints. It can be prevented from occurring. (2) By connecting the male and female joints so as to satisfy the conditions described in claim 1 in particular, they can be completely joined to each other, and a reverse force is required for the joint part depending on the situation of pile driving. Even in this case, the connection portion does not loosen. (3) The piles can be joined easily and accurately without being affected by the weather at the site of pile driving, the intuition and skill of construction engineers.
[Brief description of the drawings]
1A and 1B are longitudinal sectional explanatory views showing the structure of a pile joint of a first embodiment according to the present invention.
FIG. 2 is a perspective explanatory view of a ring-shaped reverse rotation locking member.
FIGS. 3A and 3B are a side view and a front view of the ring-shaped reverse rotation locking member of FIG.
FIG. 4 is an explanatory view showing a relationship between a surface of the male and female joints pressed against each other and a contact surface of the screw portion.
FIG. 5 is an explanatory view showing a relationship between two locations where the male and female joints are pressed against each other.
FIG. 6 is an explanatory diagram for comparing the strengths when the male and female joints are in contact with each other by being pressed at one place and at two places.
7 (A) and 7 (B) are longitudinal sectional explanatory views showing a pile joint of a second embodiment of the present invention.
FIGS. 8A and 8B are longitudinal sectional explanatory views showing pile joints of the third embodiment and the fourth embodiment, respectively.
FIGS. 9A and 9B are longitudinal sectional explanatory views showing a pile joint of a fifth embodiment.
FIGS. 10A and 10B are longitudinal sectional explanatory views showing a pile joint of a sixth embodiment.
FIG. 11 (A) is a diagram for explaining the operation of the reverse rotation locking mechanism, and FIG. 11 (B) is a diagram for displaying the force relationship on the slope surface of the reverse rotation locking mechanism.
FIG. 12 is a graph showing the results of a twist test of a pile joint equipped with the reverse rotation locking mechanism of the present invention.
[Explanation of symbols]
1,2 Pile body
3 Male fitting
4 Female fitting
5 steps
6 Outer diameter base
7 Screw part
8 steps
9 Screw part
10 Inner bottom
11 V groove
12,13,14,15,15 Ring-shaped reverse rotation locking member
12a, 13a, 14a, 15a Single surface
12b, 13b, 14b, 15b Single side
16,17,18,19 Ring-shaped reverse rotation locking member
16a, 17a, 18a, 19a Single surface
16b, 17b, 18b, 19b Single side

Claims

相互にネジ接続される雄継手と雌継手との間にリング状逆転緩止部材が介在された杭継手に於いて、前記リング状逆転緩止部材の片表面には３°〜６°の下り勾配を有する複数個の突起部が設けられ、該複数個の突起部が設けられたリング状逆転緩止部材の片表面全体の面積は前記雄継手と雌継手とのネジ接触面の総面積の３分の１以上の面積で、かつ前記雄継手と雌継手とで相互に押圧し合って接触される面の面積の１３０〜１６０％の面積を有していることを特徴としたネジ式杭継手。In a pile joint in which a ring-shaped reverse locking member is interposed between a male joint and a female joint that are screw-connected to each other, the surface of the ring-shaped reverse locking member has a descending angle of 3 ° to 6 °. A plurality of protrusions having a slope are provided, and the area of the entire surface of the ring-shaped reverse rotation locking member provided with the plurality of protrusions is the total area of the screw contact surfaces of the male joint and the female joint. A threaded pile having an area of 1/3 or more and having an area of 130 to 160% of the area of the male joint and female joint that are pressed against each other and contacted with each other Fittings.

雄継手と雌継手との間に介在されるリング状逆転緩止部材は単数或いは２個一対のものより構成されることを特徴とした請求項１のネジ式杭継手。2. The threaded pile joint according to claim 1, wherein the ring-shaped reverse locking member interposed between the male joint and the female joint is composed of a single member or a pair of two members.